Process for forming dental bridges and the like.



T. G. HUTCHINSON.

PROCESS FOR FORMING DENTAL BRIDGES AND THE LIKE. APPLIOATION FILED JUNE1, 1908.

Patented May 16, 1911.

WITNESSES:

aaw ak 7%. $4M,

INVENTOR.

ATTORNEY.

THOMAS C. HUTGHINSON, 0F DECORAH, IOWA,

PROCESS FOR FORMING DENTAL BRIDGES AND THE LIKE.

Specification of Letters Patent.

Patented May 16, 1911.

Application "filed. June 1, 1908. Serial No. 436,171.

To all whom it may concern:

Be it known that I. Tnouas llu'rrmx- SON, a citizen of the United tates,residing at Decorah. in the county of \Vinneshiek and State of Iowa,have invented certain new and useful Improvements in Processes forForming Dental Bridges and the Like. of which the following is adescription.

My invention relates to the production of that class of artificial orpartially artificial teeth, known as bridges. crowns and the like andthe object of my invention is to provide an accurate, convenient andextremely expeditious means for forming such teeth.

In the accompanying drawings wherein like or similar referencecharacters indicate like or corresponding parts: Figure 1, is a planview of a die plate for carrying my process into effect. Fig. 9, is asection taken substantially on line of Fig. 1. Fig. 3, is a sectiontaken substantially on line of Fig. 1. Fig. 4. is a side elevation of amodel formed in one of the cavities in the die plate. Fig. 5, is a modelinclosed in a suitable investment to form a mold.

In the preferred form shown in the drawings l. is a die plate formed ofany suitable material and provided with any desired number, form andarrangement of dies or cavities, 2. 3 and f each preferablycorresponding accurately with one or more articles or some portion ofone or more articles which it is desired to produce. In the form showneach of the cavities 2 accurately corresponds to the form and size of anormal tooth and the cavities 3 and 4: to a plurality of normal teeth intheir natural relation to each other. Several sizes of each tooth orcombination of teeth are preferably provided so that a die or cavity maybe selected which will accurately correspond with the size of the teethof any designated person.

After selecting the desired cavity to be employed in a particular case,the operator fills the cavity with any suitable substance which willaccurately conform to the shape of the cavity and retain its shape toserve as a dummy or model 5 and which may be volatilized or otherwiseeliminated by heat or other convenient agency. Preferably a sheet ofsuitable wax is first warmed over a flame or in hot water until it issufliciently plastic, then rolled to size desired to properly fill thecavity selected. The walls of the cavity are then preferably moistenedwith water or other suitable liquid and the softened wax carefullypressed into the cavity with a blunt instrument taking care to force thewax firmly against the sides 6 and 7 of the cavity and to its extremebottom 8 to insure an accurate model and the proper form at thebucco-occlusial point. Having properly filled the cavity any surplus vaxmay be removed with a heated spatula or other convenient means and thecompleted model lifted out of the die. When a bridge is being contructed the abutments should now he made and fitted to the plaster orother model which may be mounted upon an articulator in the usual or anydesired manner. The 'ax dummy or model 5 is then carefully fittedbuceally :1]l(l"lfll')lO-(llS- tally trimming or otherwise forming thesame to accurately fit in place. The wax model will readily bend toconform to the shape of the plaster model without seriously distortingorinjuring its appearance. The model is completed by carefully forming thepalatal surface to fit the plaster model so that an accurate wax modelof the finishing bridge is provided.

\Vhen it is desired to provide a porcelain facing for all or a portionof a bridge, the buccal surface of the model may be employed as apattern by which to determine the size of the facing desired, afterwhich the buccal surface may be cut from the model with a knife or othersuitable means and after oiling the pins upon the facing press the sameinto place, reinforce the cutting edge of the facing, cool or permit themodel to harden, remove the facing and insert suitable carbon points inthe pin holes, which may be readily removed after the bridge is castleaving the metal part of the bridge ready to receive the facings whichmay be easily cemented into place. A small pin or stem 9 is next forcedinto or otherwise attached to the finished model to serve as a handlefor supporting the model while it is being invested and also to serve asan inlet or runner by which molten metal may be introduced into thefinished mold. The finished. wax model is next invested in a suitablyrefractory porous material. such for example, as a mixture of plaster ofParis and silica, to form a mold or casing 10 with a suitable cup orcrucible 11 at the stem 9 to receive the molten metal.

As soon as the investing material has sufficiently set or hardened, thepin or stem 9 is withdrawn and the mold 10 is subjected to sufficientheat to vaporize or burn the wax model and completely eliminate thesame, leaving a mold with a suitably formed cavity to receive the moltenmetal to form the desired article connected by a small runner or openingto a cup or crucible 11. The

walls of the mold are sufficiently porous to permit the escape of anyimprisoned air so that when molten metal is placed in the crucibleit'may be forced into the mold to form an article.

The molten metal may be forced into the mold in any desired manner, forexample, the molten metalmay be forced into the crucible 11 from asuitably constructed pump or the air may be exhausted from the moldcavity, thus permitting the metal in the crucible to enter the moldunder ordinary atmospheric pressure, but as mechanism for forcing metalinto the mold forms no part of my present invention, a furtherdescription of thesame is unnecessary. After the cast is complete andthe metal permitted to cool the mold is broken away and the finishedarticle polished or otherwise finished, asmay be desired.

Having thus described my invention it is obvious that such immaterialmodifications may be introduced as may be found necessary or desirablefor adapting the same to particular uses hence I do not Wish to beunderstood as limiting myself to the exact construction shown.

WVhat I claim as new and desire to secure by Letters Patent is:

1. The herein described process of forming dental bridges and the like,comprising, first, providing a die or cavity of suitable form, second,inserting a suitable material in said cavity and forming a model thereofcorresponding with the form of the cavity, third, shaping the model tofit the final location of the finished article, fourth, investing saidmodel in a body of suitable re-, fractory porous material to form amold, fifth, heating said mold until the model is eliminated, andlastly, filling said mold with molten metal.

2. The herein described process of forming dental bridges and the like,comprising, first, providing a die plate having a plurality of separatedies or cavities-in its face and selecting the proper cavity, second,inserting a suitable material in said cavity and forming a model thereofcorresponding with the form of said selected cavity, third, shaping themodel to fit the final location of the finished article, fourth,investing said model in a body of suitable refractory porous material toform a mold, fifth, heating said mold until the model is eliminated, andlastly, filling said mold with molten metal.

3. The herein described process of forming dental bridges and the like,comprising, first, providing a die plate having a plu rality of separatedies or cavities in its face each provided with the impression of thelabial, occlusial and crown face of a plurality of normal teeth insubstantially their natural arrangement, second, inserting a suitablematerial in a selected cavity and forming a model thereof correspondingwith the form of the cavity, third, shaping the model to fit the finallocation of the finished article, fourth, investing said model in a bodyof suitable refractory porous material to form a mold, fifth, heatingsaid mold until the model is eliminated, and lastly, filling said moldwith molten metal.

THOMAS C. HUT'CHINSON.

Witnesses HARRY HEMPING, E. W. CUTTING.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

